【原创】MySQL和PostgreSQL 导入数据对比
在虚拟机上测评了下MySQL 和 PostgreSQL 的各种LOAD FILE方式以及时间。 因为是虚拟机上的测评，所以时间只做参考，不要太较真, 看看就好了。MySQL 工具：
1. 自带mysqlimport工具。
2. 命令行 load data infile ...
3. 利用mysql-connector-python Driver来写的脚本。
PostgreSQL 工具：
1. pgloader 第三方工具。
2. 命令行 copy ... from ...
3. 利用psycopg2写的python 脚本。
测试表结构：
mysql> desc t1;
+----------+-----------+------+-----+-------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+-----------+------+-----+-------------------+-------+
| id | int(11) | NO | PRI | NULL | |
| rank | int(11) | NO | | NULL | |
| log_time | timestamp | YES| | CURRENT_TIMESTAMP | |
+----------+-----------+------+-----+-------------------+-------+
3 rows in set (0.00 sec)
mysql> select count(*) from t1;
+----------+
| count(*) |
+----------+
|1000000 |
+----------+
1 row in set (6.80 sec) 测试CSV文件：
t1.csv
MySQL 自身的loader: （时间24妙）
mysql> load data infile '/tmp/t1.csv' into table t1 fields terminated by ',' enclosed by '"' lines terminated by '\r\n';
Query OK, 1000000 rows affected (24.21 sec)
Records: 1000000Deleted: 0Skipped: 0Warnings: 0 MySQL python 脚本：（时间23秒）
>>>
Running 23.289 Seconds
MySQL 自带mysqlimport：（时间23秒）
# time mysqlimport t_girl '/tmp/t1.csv' --fields-terminated-by=',' --fields-enclosed-by='"' --lines-terminated-by='\r\n' --use-threads=2 -uroot -proot
t_girl.t1: Records: 1000000Deleted: 0Skipped: 0Warnings: 0
real 0m23.664s
user 0m0.016s
sys 0m0.037s
PostgreSQL 自身COPY：（时间7秒）
t_girl=# copy t1 from '/tmp/t1.csv' with delimiter ',';
COPY 1000000
Time: 7700.332 ms Psycopg2 驱动copy_to方法：（时间6秒）
# python load_data.py
Running 5.969 Seconds.
Pgloader 导入CSV：（时间33秒）
# pgloader commands.load
table name read imported errors time
ytt.t1 1000000 1000000 0 33.514s
-----------------------------------------------------------------------
-----------------------------------------------------------------------
Total import time 1000000 1000000 0 33.514s
Pgloader 直接从MySQL 拉数据：（时间51秒）
# pgloader commands.mysql
table name read imported errors time
fetch meta data 2 2 0 0.138s
-----------------------------------------------------------------------
t1 1000000 1000000 0 51.136s
-----------------------------------------------------------------------
-----------------------------------------------------------------------
-----------------------------------------------------------------------
Total import time 1000000 1000000 0 51.274s
附上commands.load和commands.mysql
commands.load:
LOAD CSV
FROM '/tmp/ytt.csv' WITH ENCODING UTF-8
(
id, rank, log_time
)
INTO postgresql://t_girl:t_girl@127.0.0.1:5432/t_girl?ytt.t1
WITH skip header = 0,
fields optionally enclosed by '"',
fields escaped by backslash-quote,
fields terminated by ','
SET work_mem to '32 MB', maintenance_work_mem to '64 MB';
commands.mysql:
LOAD DATABASE
FROM mysql://python_user:python_user@192.168.1.131:3306/t_girl?t1
INTO postgresql://t_girl:t_girl@127.0.0.1:5432/t_girl?ytt.t1
with data only
SET maintenance_work_mem to '64MB',
work_mem to '3MB',
search_path to 'ytt'; 附pgloader 手册：
http://pgloader.io/howto/pgloader.1.html
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